Martin previously worked for Kay Ullrich, a SNP MSP. When she indicated she would stand down at the 2003 election, Martin was selected to be the candidate for Cunninghame North as well as being placed at the top of the SNP's list. At the election he was unsuccessful in the constituency vote, however was elected as a regional member for the West of Scotland. He was a prominent backer of Dr Bill Wilson who stood against John Swinney in the SNP leadership contest in 2003. He has been critical of the direction of the SNP since becoming an MSP, believing they are being dragged into the political centre away from their traditional left-of-centre position. He also believes the party is not vociferous enough in its advocation of Scottish independence. He was suspended from the Scottish National Party on 25 April 2004 after publicly criticising John Swinney, and was expelled from the SNP on 10 July 2004, soon after Swinney had resigned. After becoming an Independent MSP, Campbell Martin played a prominent role in fighting a number of decisions taken by Labour-led North Ayrshire Council. He has also continued his opposition to what he considers to be the centre-right re-positioning of the SNP and its advocacy of a 'culture of independence' rather than national independence. Campbell Martin stood as an Independent candidate in the Cunninghame North constituency at the May 2007 Scottish Parliament Election, securing 4,423 votes, but was not re-elected. Between 2007 and 2015, Campbell Martin edited the3towns com , an online local newspaper covering the three North Ayrshire towns of Ardrossan, Saltcoats and Stevenston. He is now the Creative Director of MacAulay Gibson Productions, an independent production company producing factual television programmes and business promos. In August 2011 he joined the Scottish Socialist Party, and on 1 October 2011 he spoke at an SSP fringe meeting in Glasgow following the STUC anti-cuts demonstration. He participated as a delegate at the SSP national conference in March 2012. He was the SSP candidate for the Ardrossan and Arran ward on North Ayrshire Council in May 2012, but he was not elected. While still producing pro-independence articles for mainly online publications, Campbell Martin is no longer a member of a political party.
